将动态内容压缩到ServletOutputStream [英] Compress dynamic content to ServletOutputStream
问题描述
我想压缩动态创建的内容,直接写入ServletOutputStream,而不在压缩之前将其保存为服务器上的文件。
I want to compress the dynamic created content and write to ServletOutputStream directly, without saving it as a file on the server before compressing.
例如, Excel工作簿和包含带有SQL模板的字符串的StringBuffer。我不想在压缩文件和写入ServletOutputStream之前将动态内容保存到服务器上的.xlsx和.sql文件。
For example, I created an Excel Workbook and a StringBuffer that includes strings with the SQL template. I don't want to save the dynamic content to .xlsx and .sql file on the server before zipping the files and writing to ServletOutputStream for downloading.
示例代码:
ServletOutputStream out = response.getOutputStream();
workbook.write(byteArrayOutputStream);
zipIt(byteArrayOutputStream,out);
public static boolean zipIt(ByteArrayOutputStream input, ServletOutputStream output) {
try {
ZipOutputStream zos = new ZipOutputStream(new BufferedOutputStream(output));
ZipEntry zipEntry = new ZipEntry("test.xlsx");
zos.putNextEntry(zipEntry);
if (input != null) {
zipEntry.setSize(input.size());
zos.write(input.toByteArray());
zos.closeEntry();
}
} catch (IOException e) {
logger.error("error {}", e);
return false;
}
return true;
}
推荐答案
创建<$ c $在 doGet()
或 doPost()
方法中创建一个 ServletOutputStream
初始化并直接写入它:
Create an HttpServlet
and in the doGet()
or doPost()
method create a ZipOutputStream
initialized with the ServletOutputStream
and write directly to it:
resp.setContentType("application/zip");
// Indicate that a file is being sent back:
resp.setHeader("Content-Disposition", "attachment;filename=test.zip");
// workbook.write() closes the stream, so we first have to
// write it to a "buffer", a ByteArrayOutputStream
ByteArrayOutputStream baos = new ByteArrayOutputStream();
workbook.write(baos);
byte[] data = baos.toByteArray();
try (ZipOutputStream out = new ZipOutputStream(resp.getOutputStream())) {
// Here you can add your content to the zip
ZipEntry e = new ZipEntry("test.xlsx");
// Configure the zip entry, the properties of the file
e.setSize(data.length);
e.setTime(System.currentTimeMillis());
// etc.
out.putNextEntry(e);
// And the content of the XLSX:
out.write(data);
out.closeEntry();
// You may add other files here if you want to
out.finish();
} catch (Exception e) {
// Handle the exception
}
}
这篇关于将动态内容压缩到ServletOutputStream的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!